Open-end wrench jaws having thrust and pull surfaces of different curvature



Aug. 3, 1954 F DIEBOLD v 2,685,219 OPEN-END WRENCH JAWS HAVING THRUST AND PULL SURFACES OF DIFFERENT CURVATURE Filed March 25, 1953 i w s 7; \!Q- s I l/ INVENTOE Frifiz Diebold.

ATTORNEY Patented Aug. 3, 1954 OPEN-END WRENCH JAWS HAVING THRUST AND PULL SURFACES OF DIFFERENT CURVATURE Fritz Diebold, Geneva, Switzerland Application March 23, 1953, Serial N 0. 344,108

Claims priority, application Switzerland March 31, 1952 3 Claims.

The present invention relates to an open-end wrench of the type in which the active part of the jaws is in the form of a boss, in such a manner that the movement of rotation by the The curvature of the zones 8 and 9- may naturally have a shape other than that of arcs of a circle. In these cases the radii R and 1 represent the average radius of curvature of said zones 8 wrench of an object of polygonal cross-section is and 9 eifected by the coming into contact of said bosses In wrenches of this type, of known construcwith two opposite faces of the polygonal object. tion, the active parts of the jaws do not have the When these wrenches are constructed of a particular shape above described. When using metal having a predetermined elasticity, for eX- such known wrenches, it is found that at a preample of steel, or when their active parts are of 10 determined moment, one of the jaws is held by too small a curvature, it is possible that during friction against the corresponding face of the too forceful actuation, the wrench jaws will slide object to be turned, while the other jaw continues over the corners of the polygonal object. to slip. The first jaw cannot slip at this moment The open-end wrench according to the invenagainst the corresponding face of the object, tion remedies this disadvantage, because the cause the object abuts against the bottom of the active part of each jaw is of a rounded shape recess in the wrench. to provide thrust and pull zones, the radius of When the resilient spacing of the jaws thus curvature of the zone of each of said active parts reaches a sufiicient value, the wrench slips on the which applies a thrust against one of the faces object. of the polygonal object, being made greater than The wrench described with reference to the that of the zone of each of said parts which apdrawing enables the above-mentioned disadvanplies a pull to the face of the object, opposite the tages to be avoided by reason of the selection of first face. the radii of curvature r and R.

One form of construction of an open-end Further, the inner surface of the wrench comwrench according to the invention is shown diaprised between the two jaws and in particular grammatically and by way of example in the the bottom of the recess in the head of the wrench accompanying drawing. is formed in such a manner that, when under The head of said wrench comprises two jaws stress, the shortest connecting line S between I and 2 of which the active parts 3 and 4 are in the active parts 3 and 4 passes practically through the form of rounded bosses. the center of the section line of the object I The bottom of the jaws l and 2 is provided which is in contact with the bosses 5 at the botwith bosses 5 also adapted to come into contact tom of the jaws. Further, the distance a sepasolely with the faces of an object of po ygonal rating one of the bosses 5 from the center point cross-section which is engaged between the jaws. of the line comiecting the two parts 3 and 4 is In the drawing, the wrench is shown in the selected larger than half the distance S sepap s t on of a t a on, that is to say when it is rating the bosses 3 and 4 when the wrench is being stressed while moving a hexagonal object in the normal unstressed position (shown in 'l in the direction of the arrow 6. broken lines) The active part 3 of the wrench thus applies Thus, when stressed during actuation of the a push against the corresponding face of the 40 object I, the anchoring points of the bosses 3 object I whilst the active part 4 app-lies a pull and 4 with the object 7, and the points of conon the face of the object I opposite the first face. tact of the bosses 5 with the latter, are located As the wrench is capable of rotating the object practically on a circle of radius a (a is therefore I in either one direction or the other, the parts approximately equal to 5). 3 and 4 are symmetrical and each thereof is It will be understood that not only open-end provided, on the outside of the jaws, with a zone wrenches with fixed jaws may be constructed in 8 by which it applies a thrust and on the inside the manner hereinbefore described, but open- W h a Z0116 9 y Wh ch it applies a pull to the end wrenches with adjustable jaws may also be object I. constructed in the same manner.

The zone 8 of each of the parts 3 and 4 by lel im; which it applies this thrust is substantially in 1. An open-end wrench for turning objects of the form of an arc of a circle of radius R and polygonal cross-section, said wrench comprising the zone 9 of each of said parts is also substantwo jaws, each of said jaws having an active tially in the form of an arc of a circle. However, part formed by a boss, said bosses coming into the zones 9 have a radius of curvature 1 which contact with two opposite faces of said object is smaller than R.

of polygonal cross-section when turning same,

said boss of each jaw being of rounded shape to provide a thrust zone and a pull zone, the radius of curvature of the zone of each of said bosses adapted to apply a thrust to one of the faces of said -object of polygonal "crossssection being greater;than that ofathe zone of eachof said bosses adapted to apply a pull on the face of said object of polygonal cross-section located opposite the first mentioned face.

2. An open-end wrenchaccofidingtoclaimil, bosses being provided at the bottom-of the space comprised between said jaws, the distance separating said bosses from the middle of-alinepassing through said active parts of said jaws when stressed being greater thanhalf thewdistance separating said active parts whenthewrench is not stressed.

3. An open-end wrench according to claim 1, the inner surface of the space comprised between said two jaws being so shaped that a line of .between the twojaws, and the wrench is being actuated.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 486,76 l Carpenter Nov. 22, 1892 -FOREIGN PATENTS Number Country Date 3,659 Great Britain Nov. 10, 1873 80,678 Sweden June 12, 1934 770,360 France June 25, 1934 

